“This will make a difference” in the treatment that obese patients get, said Dr. Rexford Ahima of University of Pennsylvania’s Institute for Diabetes, Obesity and Metabolism. “I would imagine it would cause the insurance companies to think again” about paying for weight-loss treatments, just as they do for smoking-cessation programs, Ahima said.

Harold Goldstein, executive director of the California Center for Public Health Advocacy, agreed that it could prompt health insurers to expand coverage of nutrition counseling to help people who are overweight or obese. Calling obesity a disease also could boost efforts to remove junk food from schools and pass taxes on sodas, he said.

More broadly, Goldstein said, it “will bring additional awareness of the importance of the obesity and resulting diabetes epidemic and will encourage all of us to think about what we can do to change the culture in which we live.”

BMI for adults is calculated by taking your weight (measured in kilograms) and dividing it by the square of your height (measured in meters). For those who prefer standard measurements, measure your weight in pounds, divide it by the square of your height measured in inches, and multiply the result by 703. You can also skip the math and find your own BMI by plugging a few numbers into this BMI calculator.)

Obesity in and of itself isn’t necessarily a health problem. But people who are carrying enough extra pounds to qualify are more likely to develop other problems that can be life-threatening, including type 2 diabetes, coronary heart disease, stroke and certain types of cancer, among others.

The AMA vote could lead to more doctors taking obesity more seriously, said Susan Babey, a senior researcher at the UCLA Center for Health Policy Research.

But as the AMA’s own Council on Science and Public Health noted, the new classification could have some drawbacks. Calling obesity a disease may suggest to patients that the problem can be fixed with medical treatment, Babey said. “There are things that we know help, but there is no single cure,” she said.

The new label also has the potential to make obesity more stigmatizing for patients, Babey added.

In a background report it prepared in advance of the vote, the AMA council warned that "'medicalizing' obesity could intensify patient and provider reliance on (presumably costly) pharmacological and surgical treatments to achieve a specific body weight.” It could also “detract from creative social solutions” to foster healthy behavior on the part of all Americans, the council wrote.

California Department of Public Health spokesman Matt Conens said it was too early to know how the AMA’s decision would impact his agency's work. But he said its staff would continue working to “raise awareness about the harm and dangers related to obesity.”